Die for tube profiles

ABSTRACT

A die arrangement for continuous casting tube profiles having an outer cylindrical-like die portion and a mandrel spaced in the bore of the outer die portion, the mandrel is held radially in the bore by a cylindrical collar thereon at one end fitting into a surrounding cylindrical recess in the outer die portion and is held in an axial direction by a threaded portion on the same end of the mandrel threadedly received in a surrounding threaded portion of the outer die portion. There are axially extending passageways through the collar and threaded portions of the mandrel for flow of casting material to form the tube in the space between the mandrel and the surrounding outer die portion.

llnited States Patent 1 Krall et al.

[ ,iiine 5,1973

[54] DIE FOR TUBE PROFILES [73] Assignee: Technica-Guss GmbH, Wurzburg,

Germany 22 Filed: Jan.22, 1971 211 Appl.No.: 108,758

[30] Foreign Application Priority Data Jan. 30, 1970 Germany ..P 20 04193.4

[52] US. Cl. ..164/281, 164/85, 425/380 [51] Int. Cl. ..B22d 11/10 [58]Field of Search ..164/85, 281; 425/380; 72/266, 267, 268

[56] References Cited UNITED STATES PATENTS 3,375,863 4/1968 Atkin et al..164/85 X 2,466,612 4/1949 Phillips et a1. ....l64/85 X 670,611 3/1901Hoffman ..425/380 2,924,332 Lawton et al ..72/268 X 2,981,409 4/1961Colleoni ..72/268 2,243,031 5/1941 Fogg t 72/268 3,302,440 2/1967 Seidelet al. ..72/268 X 3,578,065 5/1971 Langer ..164/85 X Primary Examiner-J.Spencer Overholser Assistant Examiner.lohn E. Roethel Attorney-Jones &Lockwood [57] ABSTRACT A die arrangement for continuous casting tubeprofiles having an outer cylindrical-like die portion and a mandrelspaced in the bore of the outer die portion, the mandrel is heldradially in the bore by a cylindrical collar thereon at one end fittinginto a surrounding cylindrical recess in-the outer die portion and isheld in an axial direction by a threaded portion on the same end of themandrel threadedly received in a surrounding threaded portion of theouter die portion. There are axially extending passageways through thecollar and threaded portions of the mandrel for flow of casting materialto form the tube in the space between the mandrel and the surroundingouter die portion.

4 Claims, 4 Drawing Figures Patented June 5, 1973 3,736,79

3 Sheets-Sheet 2 Patented June 5, 1973 3 Sheets-Sheet 3 DIE FOR TUBEPROFILES BACKGROUND OF THE INVENTION The invention concerns a die fortube profiles.

For the production of tubes by the continuous casting method it iscommon to use a die consisting of a cylindrical outer die portion and ofa mandrel attached in the middle thereof. This mandrel can be mounted inthe die portion by means of a press fit. There is, however, a possiblitythat the mandrel might move back into the furnace during production,because the press fit may not suffice for holding the mandrel, due tothe high thermal stress during operation. There is another way to attachthe mandrel to the outer die portion by means of threads. In this casethe mandrel is held in its position there within, but it is verydifficult to manufacture these threads in such a way that the mandrel ispositioned centrally within the outer die portion in all cases.

The invention is meant to avoid these disadvantages.

The problem is solved by holding the mandrel by means of a cylindricalcollar in a cylindrical recess of the outer liner or outer die portionin radial direction, and by means of threads in axial direction. Thus, acentral position of the mandrel is achieved and it cannot be pushed outof the die.

BRIEF DESCRIPTION OF THE DRAWINGS An example of the invention is shownin the drawing, and will be described in detail in the followingparagraph.

FIG. 1 an end view of the arrangement as viewed from the furnace,

FIG. 2 a longitudinal section of the arrangement in FIG. 1 as viewedalong section line 2-2,

FIG. 3 is an end view of a separate annular element that may replace thecentering cylindrical collar portion on the mandrel and FIG. 4 is afragmentary drawing showing a modified mandrel with the separate annularelement of FIG. 3 installed in the outer cylindrical liner or dieportion, the section of the mandrel is taken through a solid portion.

DETAILED DESCRIPTION There is an outer cylindrical liner or die portion1 formed at the entrance end with a cylindrical recess 5 slightly largerthan the bore of the die portion thereby leaving a shoulder at 5a andout from the recess 5 a further enlarged threaded recess 5b. A mandrel 2is received in the outer die portion 1 and a short cylindrical collar 4having a corresponding diameter to that of recess 5 is received thereinand holds the mandrel centered in a radial direction. The shoulder 5aprevents the mandrel from inclining its axis relative to the axis of theouter die portion 1 caused by its dead weight. A threaded portion 3 onan enlarged entrance end of the mandrel is threadedly received in thethreads 5b of the outer die portion entrance end to hold the mandrelfrom being pushed axially out of the surrounding die portion 1 and topress it against the shoulder 5a. Axially extending apertures 6 aremachined in the collar 4 at its entrance end to provide passageways fromthe holding furnace for molten metal to enter the bore of the outer dieportion 1 and about the mandrel 2 to form a tube. The outer die portion1 and the mandrel 2 may be fabricated from graphite.

The cylindrical collar 4 while shown in FIGS. 1 and 2 as integral withthe mandrel could be a separate annular element 40 such as shown in FIG.3 and in FIG. 4 installed on a modified mandrel 2a. The annual element4a centers the mandrel in a radial direction within the cylindricalliner or die portion 1.

What is claimed is:

1. A die arrangement for tube profiles comprising an outer die portionor liner having a bore therethrough, a threaded recessed entrance endlarger than said bore and a cylindrical recess adjacent the threadedrecessed end having a diameter intermediate that of the bore and thethreaded recessed end thereby forming a radially extending shoulderportion at the bore end of the cylindrical recess; a mandrel received inspaced relation within the bore of the liner or outer die portion andhaving an enlarged threaded end received within the threaded entranceend of the outer liner, a cylindrical collar portion of correspondingdiameter to that of the cylindrical recess in the outer liner andreceived therein and axially extending apertures in the enlargedthreaded end collar providing passageways for molten metal to enter tothe bore of the outer die portion and about the mandrel, whereby themandrel is held concentrically within the liner or outer die portion andin a radial direction by the cylindrical collar and the cylindricalrecess and held in an axial position by said threaded portions.

2. A die arrangement according to claim 1 fabricated from graphite.

3. A die arrangement for tube profiles according to claim 1 wherein saidcylindrical collar is a separate annular member received over anadjacent cylindrical portion on the mandrel to hold the mandrel radiallywithin the outer liner.

4. A die arrangement according to claim 3 fabricated from graphite.

1. A die arrangement for tube profiles comprising an outer die portionor liner having a bore therethrough, a threaded recessed entrance endlarger than said bore and a cylindrical recess adjacent the threadedrecessed end having a diameter intermediate that of the bore and thethreaded recessed end thereby forming a radially extending shoulderportion at the bore end of the cylindrical recess; a mandrel received inspaced relation within the bore of the liner or outer die portion andhaving an enlarged threaded end received within the threaded entranceend of the outer liner, a cylindrical collar portion of correspondingdiameter to that of the cylindrical recess in the outer liner andreceived therein and axially extending apertures in the enlargedthreaded end collar providing passageways for molten metal to enter tothe bore of the outer die portion and about the mandrel, whereby themandrel is held concentrically within the liner or outer die portion andin a radial direction by the cylindrical collar and the cylindricalrecess and held in an axial position by said threaded portions.
 2. A diearrangement according to claim 1 fabricated from graphite.
 3. A diearrangement for tube profiles according to claim 1 wherein saidcylindrical collar is a separate annular member received over anadjacent cylindrical portion on the mandrel to hold the mandrel radiallywithin the outer liner.
 4. A die arrangement according to claim 3fabricated from graphite.